The Telemetry Data Handling System (TDHS) at the Telemetry Data Center in White Sands Missile Range (WSMR), New Mexico, has been in operation since January 1990. It is one of the world's largest integrated range telemetry systems, and certainly the most versatile in weapons support capability. The system supports one of the world's busiest test ranges, serving all U.S. Military Services as well as NASA and others. This paper looks at the White Sands system from the user's view, examining the ways in which it is configured for several weapons tests in a typical day, and the way in which it can run foreground launch support and background pre-launch activities simultaneously. This system has grown in functional capability since its installation, both in hardware and in software. This paper analyzes that growth to see the reasons and methods. Also, near-term additional growth is addressed.

The Aircraft Research and Development Unit (ARDU) is the flight test authority for the Royal Australian Air Force (RAAF). ARDU was born out of a requirement to handle the testing of developmental aircraft and weapons during Word War II. Its nucleus was established in 1941 and one of its first tasks was to evaluate the flying qualities and performance of captured Japanese aircraft. Today, ARDU provides "one-stop shopping" for flight testing all aircraft, weapons and systems in the RAAF and Australian Army Inventory. As directed by the RAAF, ARDU also performed flight testing on Royal Australian Navy aircraft, as well as novel and unique aircraft such as lighter-than-air and museum restored aircraft that are of historical importance.

The parallel processing technology has been widely applied to many science and engineering technical fields, also to telemetry. In particular, telemetry develops towards the trend of large capacity, high rate, several data streams and programmable formats. This sets a still higher demand on processing for real-time multilexing telemetry data. On the basis of analyzing of the characteristics of telemetry data processing (TDP), the parallel processing conception and methods are adopted, countering multiiple-channel data streams of different objects, several architectures of parallel processing for real-time multiplexing telemetry data are presented. It makes better use of the concurrency during the process of TDP and handles the telemetry information effectively in every processing level of the whole telemetering information processing system. The paper shows the property comparison of these parallel processing architectures and main features too. Experiments have indicated that it is an economical and effective method to improve the performance of telemetry information processing system by using paralle processing architecture which is based on concurrency of telemetry data processing.

ASW-II (Advanced Satellite Workstation, Version II) has been developed and delivered as an operational prototype in support of the Ultra High Frequency (UHF) Follow-On satellite. It provides unified and coordinated real time reception and storage of satellite telemetry, display of both real time and stored telemetry, expert-system analysis of spacecraft status, and an information navigator system that stores and presents information about the spacecraft. The architecture is modular and reconfigurable, and it provides support for multiple analyst workstations. There are several unusual aspects of the design. The entire telemetry history of the satellite is regarded as a continuum by the user, with ASW-II automatically tracking and displaying contact periods. A "streams" mechanism organizes the telemetry in such a way that the user can interactively define new derived parameters and have them presented graphically. Both real time and archived data can be displayed simultaneously. The user has very flexible controls for all display interfaces using mouse and window technologies.

The principle behind delta modulation systems is introduced. Having developed the principles of delta modulation systems, a system that performs delta modulation is developed and tested to see how well the system performs by using sinusoids and speech as the input to the system. This is then followed by a comparison of delta modulation and pulse code modulation to show that, overall, delta modulation is better than pulse code modulation.

Due to the complexity of real-time missions, an increasing number of participants, and the critical nature of test missions, providing a reliable, versatile voice communication network for mission support entities has become essential. A voice communication system has a direct impact on the effectiveness of every mission and the safety of mission personnel. Each participant must satisfy unique functional and operational communication requirements. This paper addresses the functional, operational, and ergonomic aspects associated with a voice communication system for the Central Control Facility (CCF) at the Air Force Development Test Center (AFDTC), Eglin AFB, Florida. The communication system was purchased from an Edwards AFB Digital Switch requirements contract.

Chart recorders currently in use on telemetry ranges are connected to telemetry processors via a series of Digital to Analog Converters (DAC) systems. A new modular interface system receives data directly from the processor broadcast bus and distributes them to up to ten digital chart recorders. This interface is programmed from a computer to assign individual tags to each one of the display channels. This system eliminates DAC's and patch panels. It simplifies display system operation, speeds up transition from test to test and reduces maintenance costs.

Pulse Code Modulation (PCM) Encoders are extensively used in instrumentation and telemetry systems. Commercially available encoders are available from several sources and vary in complexity depending on the application. Encoders often include analog signal conditioning, a system clock, and one or more digital input ports. Many of these systems also cost several thousand dollars and the cost goes up when high data accuracy of one or two percent is required. This paper describes a low cost approach which has been used in production telemetry applications with great success and which yields a PCM encoder with data accuracies of better than 2%.

Real-time computation speed is an additional requirement for simulations. It is necessary for 'man-in-the-loop' systems like flight simulators and for 'hardware-in-the-loop' systems where real components like new closed loop controllers are tested under realistic conditions. In the past a lot of companies have designed and built special purpose simulation computers which are very powerful but expensive and not handy enough for 'in-the-field-tests'. The progress in computer science shows a trend to distributed systems where multiple processors are running in parallel to improve the performance dramatically. At the DLR Institute for Flight Mechanics a computer system, based on the transputer, was designed to achieve the real-time simulation capabilities for the ROTEST model rotor. This four-bladed rotor is a 2.5 scale of the BO105 main rotor, equipped with elastic blades, operating at 1050 rpm. After an introduction to the ROTEST rotor, including the demands upon the simulation, a short introduction to transputers and the associated philosophy is given. The next part of the paper presents the characteristics of the simulation model, its mathematical description and the transputer architecture on which it is running. In the last part of the paper the input and output processes to the simulation are described. This includes a real-time representation of the rotor and an oscilloscope like output device, as well as analogue input and output devices to a controller.

This paper describes a C-band auto-tracking receiving system on shipboard which is used in satellite telemetry. The system consists of receiving antenna, wideband feed, antenna pedestal, telemetry/tracking receiver antenna controller and computer console. Its characteristics are as follow: Single Channel Single Pulse Tracking Feed, 2. 5m Antenna Diameter, 500MHz BW, LHCP and RHCP Dual - Channel Polarization Diversity Receiving. The servo system uses rate - gyros as stabilized element being based on the micro - processor to realize the digital servo control. Computer console performs the status monitoring and management to the whole system. The system design, the main system specification and important test results are given.

This paper describes a CSC² single axis tracking antenna using a single channel monopulse antenna which has improved sidelobe performance over conventional single channel monopulse antennas. Effective sidelobes of the composite pattern, measured at the receiver input, greater than 22 dB have been achieved. This is due to a unique feed design. The composite patterns are the true measure of performance for a single channel monopulse system since this is the input to the tracking receiver. The low effective sidelobes result in a significant reduction of multi-path problems.

Today's complex implementations of integrated packet and circuit switched digital communications networks demand that the software used for controlling these systems be robust, fault tolerant, and capable of runtime recovery from all but the most severe of operational errors. The typical modern switched communications system includes the use of multiple circuit switches, each with potentially thousands of end-user interfaces. Further, these switches are often inter-connected to each other via high-capacity trunks. A single connection between two end-user interfaces often traverses a number of intermediate circuit switches in order to effect the end-to-end communications desired. In this complex, distributed environment, the establishment and dissolution of end-to-end user connections involve far more than simple binary connection states indicating the existence, or non-existence, of a link. More commonly, a single end-to-end connection requires multiple node links across multiple, heterogeneous interfaces. The command and control software used to establish, monitor, and dissolve these connections must be capable of dealing with errors which arise at any node along the way in a consistent and reliable manner. Most critically, the system software must be capable of maintaining an accurate, multi-level mapping of distributed resources' availability, allocation, and status. Further, the software must have the capability of "healing itself" during operational run-time when it can, and of accurately reporting the nature of inconsistencies caused by anomalous events that cannot be fixed on the fly. The Edwards Digital Switch (EDS), developed by CSTI, provides a case study of possible solutions, and potential pitfalls, that can arise in the design, development, and implementation of the controlling software in today's dynamic, distributed communications' system architectures.

This paper looks into the use of neural network software as applied to the classical signal to noise concern when dealing with space to ground data communications. Use of a digital neural network to extend the correlation range of Pulse Code Modulation (PCM) down into noise is investigated. Conventional synchronization pattern correlation is done with digital logic comparisons on a sliding window with a set number of bit mismatch errors allowed. Correlation with a neural network does pattern recognition with a weighted network of artificial neurons that have been trained to recognize the sync pattern within noise. The output of such a neural network will produce a best guess of the correct pattern.

In this paper we describe an object-oriented software system for realtime telemetry data management and display. The system has also been designed to be used as the primary means of data management during post-mission activities. The software system consists of three parts: the data interface library, the data format specification and the display applications. The data interface library contains a set of object definitions and procedures to provide uniform access to heterogeneous data streams. The data format specification is used by the data interface library to extract data from the raw data stream. The display applications use the data interface library to access the data and present it to the user. Currently, the interface between the data format specification and the data interface library is implemented procedurally and is modeled after a device driver. Each format is assigned a unique id and then accessed via that id. A data stream may be accessed by any number of different format specifications. A future implementation will separate the data format specification into a separate process with a message or RPC based interface. Therefore the data may be kept on remote systems and accessed in a transparent fashion. In addition, this model will support operation in distributed heterogeneous computing environments. This system handles multiple simultaneous data streams and applications can access data from different streams relatively transparently. This is possible since data variables (objects) to be displayed are specified by a syntax that contains the specification of both the data streams and the format to use. In addition, the concept of a primary stream is introduced to allow the user to scroll through one data stream and have the other streams follow. Synchronization between streams is based on time information in the data streams. Several applications have been written including various stripchart displays a tabular display and some other custom displays. A data analysis application similar to the UNIX program "awk" is currently under development. It will provide the user with the ability to extract data, i.e., report generation, for display or further analysis in an object-oriented manner.

In this paper the performance of a (1,2)-convolutional encoder combined with continuous phase modulation is simulated. A binary sequence is used inconjunction with the above encoder and a modulation index of (h=1/4). A full response 1REC frequency shaping function is used to maintain phase continuity. A binary (uncoded)CPM with the above modulation index is also simulated. The performance in terms of the probability of bit error event is plotted against signal to noise ratio for both coded and the uncoded CPM schemes. The asymptotic performance of both schemes is plotted along with MSK for comparison purposes. The simulation algorithm used in this paper utilizes the Block Oriented System Simulator known as BOSS. The major components of this simulation are the encoder and the decoder. The encoder consists of binary random data generator and a (1,2)-convolutional encoder combined with a channel vector encoder and a random white gaussian noise generator. The decoder consists of the following modules: sequential vector bank, inner product unit, metric calculator unit, multi stage trellis, symbol decoder and error counter module.

This paper addresses the distributed systems implementation techniques used in the development of the EMR O/S90 Open Systems Telemetry System. Specifically, it presents the integration, networked load-balancing, and remote control aspects of the telemetry system which allow it to adapt to differing configurations and availability of resources.

Veda Systems Incorporated has recently completed the development of a completely open architecture, UNIX-based software environment for standard telemetry and more generic data acquisition applications. The new software environment operates on many state-of-the-art high-end workstations and provides a workstation independent, multiuse platform for front-end system configuration, database management, real-time graphic data display and data, logging.

In a PCM/FM+FM/FM system, the PCM data is added to the subcarriers at baseband and the composite signal is modulated onto the carrier. When the subcarrier messages are demodulated, part of the PCM signal's spectrum falls within the bandwidth of the subcarrier bandpass filters. This causes interference with the subcarrier messages, particularly those of the lower subcarrier frequencies. When designing a PCM/FM+FM/FM system, one is concerned with the placement of the subcarrier frequencies and the interference suffered by the subcarriers due to the PCM signal. This paper develops a relationship between the lowest frequency subcarrier, PCM bit rate and the resulting interference. The design procedure allows a bit rate or lowest frequency subcarrier to be selected for a specified interference ratio. The expression of the ratio is a complex integral which is reduced to a simple equation involving the system parameters.

This paper describes a biotelemetric application whereby information of tooth contact pressure from within the mouth of a human subject is transmitted to a bedside receiver where it is processed and used in the biofeedback treatment of nocturnal bruxism (grinding of the teeth). Bruxing information is encoded on a pulse width modulated 313 MHZ carrier. Issues that are addressed include miniaturization of the transmitter, minimization of power requirements, stabilization of carrier frequency, receiver selection, and the various problems associated with getting a radio frequency signal out of the mouth.

In this paper we describe the flight software for the SETS (Shuttle Electrodynamic Tethered System) experiment. The SETS experiment will fly as part of the TSS-1 (Tethered Satellite System) experiment on STS-46 currently scheduled for July 1992. The software consists of two major components: the SETSOS (SETS Operating System) and the SETS Application. The SETSOS is a UNIX-like operating system developed especially for realtime data acquisition, instrument control and command processing. The SETSOS, like all operating systems, provides resource management for application programs. It is UNIX-like in that access to resources is provided through a standard set of UNIX system calls. The SETSOS also implements the standard UNIX I/O model and a hierarchical file system. In addition to providing access to physical devices, the SETSOS provides support for two virtual devices: a packet-based data device and a command device. The packet-based data device is used by applications to place data into the telemetry stream. The command device is used to manage commands from the command uplink as well as other sources including other applications and other processors. The SETS Application is the primary program which runs under the SETSOS to handle data acquisition, instrument control and command processing. It executes as 5 separate processes, each performing a special task. The tasks include housekeeping data acquisition, limit checking, timeline management, and command processing. The processes communicate via shared memory. Time critical processing is coordinated by using signals and interrupts. In addition to a description of the software, we will discuss the relative merits and tradeoffs of using such a system design for command processing and data acquisition.

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